fn main() {
    let a = Some(String::from("Bomb"));
    println!("{}", match &a {
        //Some("Bomb") => "Boooomb!",
        // type mismatch error: expected String, got &str
        // How to make the line above work? The line below works as expected,
        // but it is too complicated.

        Some(inner) if inner == "Bomb" => "Boooomb!",
        // What is the type of `inner` here?
        // Seems that it depends on the type of value on the right (here the
        // "Bomb"):
        // When I try to change the right-side operand to be of different types
        // in order to let the compiler report the type of `inner`. Sometimes it
        // is "String" (e.g. for 8u8), other times it is "&String" (e.g. for
        // b"Bomb").
        // If it is the expected behaviour, could you please tell me what the
        // feature is called? I did not see explanations on it before.
        _ => "_"
    });
}